Small cracks running parallel to grain of wood, caused chiefly by strains produced in seasoning. These are different from flexor cracks which are small cracks put into wood as a result of mechanical flexing process.
Numerous, very fine cracks in a coating or at the surface of a metal part. Checks may appear during processing or during service and are most often associated with thermal treatment or thermal cycling. Also called check marks. checking, or heat checks.
Lengthwise separation of wood fibers that extends across the annual growth rings. Commonly caused by stresses during drying. Surface checks occur on flat faces of lumber and end checks occur on the ends of lumber, logs, and other wood products.
and Balances: A system of limits imposed by the Constitution of the United States on all branches of a government by vesting in each branch the right to amend or void those acts of another that fall within its jurisdiction.
The Checks are the make-up and hair checks that are carried out before each 'take'. These are done to ensure good continuity for the scene. They can be rather repetitive but you should always be patient with the staff - they are doing their job.